// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
// Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1@gmail.com>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_COMMAINITIALIZER_H
#define EIGEN_COMMAINITIALIZER_H

namespace Eigen {

/** \class CommaInitializer
  * \ingroup Core_Module
  *
  * \brief Helper class used by the comma initializer operator
  *
  * This class is internally used to implement the comma initializer feature. It is
  * the return type of MatrixBase::operator<<, and most of the time this is the only
  * way it is used.
  *
  * \sa \blank \ref MatrixBaseCommaInitRef "MatrixBase::operator<<", CommaInitializer::finished()
  */
template <typename XprType> struct CommaInitializer
{
    typedef typename XprType::Scalar Scalar;

    EIGEN_DEVICE_FUNC
    inline CommaInitializer(XprType& xpr, const Scalar& s) : m_xpr(xpr), m_row(0), m_col(1), m_currentBlockRows(1)
    {
        eigen_assert(m_xpr.rows() > 0 && m_xpr.cols() > 0 && "Cannot comma-initialize a 0x0 matrix (operator<<)");
        m_xpr.coeffRef(0, 0) = s;
    }

    template <typename OtherDerived>
    EIGEN_DEVICE_FUNC inline CommaInitializer(XprType& xpr, const DenseBase<OtherDerived>& other)
        : m_xpr(xpr), m_row(0), m_col(other.cols()), m_currentBlockRows(other.rows())
    {
        eigen_assert(m_xpr.rows() >= other.rows() && m_xpr.cols() >= other.cols() && "Cannot comma-initialize a 0x0 matrix (operator<<)");
        m_xpr.block(0, 0, other.rows(), other.cols()) = other;
    }

    /* Copy/Move constructor which transfers ownership. This is crucial in 
   * absence of return value optimization to avoid assertions during destruction. */
    // FIXME in C++11 mode this could be replaced by a proper RValue constructor
    EIGEN_DEVICE_FUNC
    inline CommaInitializer(const CommaInitializer& o) : m_xpr(o.m_xpr), m_row(o.m_row), m_col(o.m_col), m_currentBlockRows(o.m_currentBlockRows)
    {
        // Mark original object as finished. In absence of R-value references we need to const_cast:
        const_cast<CommaInitializer&>(o).m_row = m_xpr.rows();
        const_cast<CommaInitializer&>(o).m_col = m_xpr.cols();
        const_cast<CommaInitializer&>(o).m_currentBlockRows = 0;
    }

    /* inserts a scalar value in the target matrix */
    EIGEN_DEVICE_FUNC
    CommaInitializer& operator,(const Scalar& s)
    {
        if (m_col == m_xpr.cols())
        {
            m_row += m_currentBlockRows;
            m_col = 0;
            m_currentBlockRows = 1;
            eigen_assert(m_row < m_xpr.rows() && "Too many rows passed to comma initializer (operator<<)");
        }
        eigen_assert(m_col < m_xpr.cols() && "Too many coefficients passed to comma initializer (operator<<)");
        eigen_assert(m_currentBlockRows == 1);
        m_xpr.coeffRef(m_row, m_col++) = s;
        return *this;
    }

    /* inserts a matrix expression in the target matrix */
    template <typename OtherDerived> EIGEN_DEVICE_FUNC CommaInitializer &operator,(const DenseBase<OtherDerived>&other)
    {
        if (m_col == m_xpr.cols() && (other.cols() != 0 || other.rows() != m_currentBlockRows))
        {
            m_row += m_currentBlockRows;
            m_col = 0;
            m_currentBlockRows = other.rows();
            eigen_assert(m_row + m_currentBlockRows <= m_xpr.rows() && "Too many rows passed to comma initializer (operator<<)");
        }
        eigen_assert((m_col + other.cols() <= m_xpr.cols()) && "Too many coefficients passed to comma initializer (operator<<)");
        eigen_assert(m_currentBlockRows == other.rows());
        m_xpr.template block<OtherDerived::RowsAtCompileTime, OtherDerived::ColsAtCompileTime>(m_row, m_col, other.rows(), other.cols()) = other;
        m_col += other.cols();
        return *this;
    }

    EIGEN_DEVICE_FUNC
    inline ~CommaInitializer()
#if defined VERIFY_RAISES_ASSERT && (!defined EIGEN_NO_ASSERTION_CHECKING) && defined EIGEN_EXCEPTIONS
        EIGEN_EXCEPTION_SPEC(Eigen::eigen_assert_exception)
#endif
    {
        finished();
    }

    /** \returns the built matrix once all its coefficients have been set.
    * Calling finished is 100% optional. Its purpose is to write expressions
    * like this:
    * \code
    * quaternion.fromRotationMatrix((Matrix3f() << axis0, axis1, axis2).finished());
    * \endcode
    */
    EIGEN_DEVICE_FUNC
    inline XprType& finished()
    {
        eigen_assert(((m_row + m_currentBlockRows) == m_xpr.rows() || m_xpr.cols() == 0) && m_col == m_xpr.cols() &&
                     "Too few coefficients passed to comma initializer (operator<<)");
        return m_xpr;
    }

    XprType& m_xpr;            // target expression
    Index m_row;               // current row id
    Index m_col;               // current col id
    Index m_currentBlockRows;  // current block height
};

/** \anchor MatrixBaseCommaInitRef
  * Convenient operator to set the coefficients of a matrix.
  *
  * The coefficients must be provided in a row major order and exactly match
  * the size of the matrix. Otherwise an assertion is raised.
  *
  * Example: \include MatrixBase_set.cpp
  * Output: \verbinclude MatrixBase_set.out
  * 
  * \note According the c++ standard, the argument expressions of this comma initializer are evaluated in arbitrary order.
  *
  * \sa CommaInitializer::finished(), class CommaInitializer
  */
template <typename Derived> EIGEN_DEVICE_FUNC inline CommaInitializer<Derived> DenseBase<Derived>::operator<<(const Scalar& s)
{
    return CommaInitializer<Derived>(*static_cast<Derived*>(this), s);
}

/** \sa operator<<(const Scalar&) */
template <typename Derived>
template <typename OtherDerived>
EIGEN_DEVICE_FUNC inline CommaInitializer<Derived> DenseBase<Derived>::operator<<(const DenseBase<OtherDerived>& other)
{
    return CommaInitializer<Derived>(*static_cast<Derived*>(this), other);
}

}  // end namespace Eigen

#endif  // EIGEN_COMMAINITIALIZER_H
